Although widespread speculation has connected aspartame exposure to all sorts of health conditions, diseases and symptoms, scientific research does not substantiate such claims. Clinical studies have encouraged major world health organizations to maintain positions that aspartame is safe for human consumption, particularly as a sugar substitute.
One of the most serious health concerns regarding aspartame consumption is the proposed threat of cancer. To investigate, researchers have performed two types of testing: one that exposes animals to the substance, often in extreme doses, and another that monitors instances of cancer among various subsets of people. Although not always easy to interpret, neither form of testing suggests a link between cancer development and aspartame ingestion that chance does not otherwise explain.
Other conditions or symptoms associated with aspartame since its introduction include Alzheimer's disease, attention deficit disorder, Gulf War syndrome, lupus, Parkinson's disease and seizures; however, neither the United States Food and Drug Administration nor the European Food Safety Authority have reversed previous endorsements for the product. Instead, they advise concerned consumers to either avoid aspartame if the prospect bothers them or to limit daily intake to prescribed levels. The FDA suggests 50 milligrams per day per kilogram of body weight, while the EFSA recommends 40.